Method and apparatus for ntn coverage enhancement for pucch and pusch

Abstract

Methods and apparatus are provided for non-terrestrial network (NTN) coverage enhancement. A user equipment (UE) sends, to a network node of the NTN, an indication of a UE capability for a physical uplink control channel (PUCCH) repetition of a fourth message (Msg4) Hybrid Automatic Repeat Request Acknowledge (HARQ-ACK) transmission in a random-access channel (RACH) procedure. The UE determines, during the RACH procedure, a trigger for the PUCCH repetition of the Msg4 HARQ-ACK transmission. In response to the trigger, the UE transmits one or more Msg4 HARQ-ACK repetitions from the UE to the network node.

1 . A method for a user equipment (UE), the method comprising:
 sending, from the UE to a network node of a non-terrestrial network (NTN), an indication of a UE capability for a physical uplink control channel (PUCCH) repetition of a fourth message (Msg4) Hybrid Automatic Repeat Request Acknowledge (HARQ-ACK) transmission in a random-access channel (RACH) procedure;   determining, during the RACH procedure, a trigger for the PUCCH repetition of the Msg4 HARQ-ACK transmission; and   in response to the trigger, transmitting one or more Msg4 HARQ-ACK repetitions from the UE to the network node.   
     
     
         2 . The method of  claim 1 , wherein sending the indication comprises sending a capability signal from the UE to the network node. 
     
     
         3 . The method of  claim 2 , wherein the capability signal indicates whether or not the UE supports the PUCCH repetition of the Msg4 HARQ-ACK transmission. 
     
     
         4 . The method of  claim 2 , wherein the capability signal indicates a number of transmissions supported by the UE for the PUCCH repetition of the Msg4 HARQ-ACK transmission. 
     
     
         5 . The method of  claim 4 , wherein the capability signal comprises a four-bit bitmap to indicate the number of transmissions. 
     
     
         6 . The method of  claim 2 , wherein the capability signal indicates an upper bound of a number of transmissions supported by the UE for the PUCCH repetition of the Msg4 HARQ-ACK transmission. 
     
     
         7 . The method of  claim 6 , wherein the capability signal comprises a two-bit bitmap to indicate the upper bound of the number of transmissions. 
     
     
         8 . The method of  claim 1 , wherein sending the indication comprises sending a physical random access channel (PRACH) message from the UE to the network node in the RACH procedure. 
     
     
         9 . The method of  claim 8 , further comprising using PRACH preambles to indicate different UE capabilities for the PUCCH repetition of the Msg4 HARQ-ACK transmission. 
     
     
         10 . The method of  claim 9 , further comprising using RACH occasions to indicate the different UE capabilities for the PUCCH repetition of the Msg4 HARQ-ACK transmission. 
     
     
         11 . The method of  claim 10 , further comprising:
 receiving, at the UE, a system information block (SIB) comprising a mapping rule between the different UE capabilities for the PUCCH repetition of the Msg4 HARQ-ACK transmission and a plurality of sets of the PRACH preambles and the RACH occasions;   determining a particular set of the plurality of sets of the PRACH preambles and the RACH occasions based on the UE capability for the PUCCH repetition of the Msg4 HARQ-ACK transmission;   selecting a particular PRACH preamble and a particular RACH occasion from the particular set; and   transmitting, from the UE to the network node, the PRACH message using the particular PRACH preamble and the particular RACH occasion for the RACH procedure.   
     
     
         12 . The method of  claim 11 , wherein the PRACH message is one of a first message (Msg1) transmission from the UE to the network node in a Type-1 random access procedure or a message A (MsgA) transmission from the UE to the network node in a Type-2 random access procedure. 
     
     
         13 . The method of  claim 11 , wherein the SIB is selected from a group comprising a system information block type 1 (SIB1), a system information block type 19 (SIB19), and a system information block type associated with NTN communication. 
     
     
         14 . The method of  claim 1 , wherein sending the indication comprises sending the indication in a third message (Msg3) physical uplink shared channel (PUSCH) transmission in a Type-1 random access channel procedure or a message A (MsgA) PUSCH transmission in a Type-2 random access channel procedure. 
     
     
         15 . The method of  claim 14 , wherein different sets of UE contention resolution identifiers (IDs) indicate different UE capabilities for the PUCCH repetition of the Msg4 HARQ-ACK transmission. 
     
     
         16 . The method of  claim 1 , wherein the indication comprises a joint indication of the UE capability for the PUCCH repetition of the Msg4 HARQ-ACK transmission and the trigger of the PUCCH repetition of the Msg4 HARQ-ACK transmission. 
     
     
         17 . The method of  claim 16 , further comprising transmitting at least one of a dedicated preamble and a dedicated RACH occasion corresponding to the joint indication only when the UE has the UE capability for the PUCCH repetition of the Msg4 HARQ-ACK transmission and the UE determines the trigger. 
     
     
         18 . The method of  claim 1 , wherein sending the indication comprises sending the indication via a media access control (MAC) control element (CE) comprising a bitmap configured to indicate a supported repetition number or a reserved bit to indicate the UE capability for the PUCCH repetition of the Msg4 HARQ-ACK transmission. 
     
     
         19 . The method of  claim 1 , wherein sending the indication comprises sending the indication via a media access control (MAC) control element (CE) carried in a third message (Msg3) physical uplink shared channel (PUSCH) transmission in a Type-1 random access procedure or a message A (MsgA) PUSCH transmission in a Type-2 random access procedure. 
     
     
         20 . The method of  claim 1 , further comprising receiving, from the network node at the UE, a repetition number for the PUCCH repetition of the Msg4 HARQ-ACK transmission. 
     
     
         21 - 38 . (canceled)